1. Field of the Invention
The present invention relates to the processing of bakers' dough. More specifically, the invention relates to processing methods and systems for forming and dividing a dough stream that are particularly well suited for the processing of specialty dough, for example.
2. Description of the Related Art
In a typical commercial bread making process for the manufacture of fine grain bread products, i.e. white bread, hamburger buns, etc, baker's dough, which is primarily made of flour and water, is blended in a large mixer. A particularly high water content usually is desirable in the dough composition formed in the mixer because a high water content tends to make a softer baked product (approximately 60 pounds of water per 100 pounds of flour is common for fine grain bread products). Gluten, which is a component of flour, absorbs and retains the water so that a dough of a sticky, paste-like consistency is made. After mixing, the sticky dough typically is then transferred to a stuffing pump which forms the dough into a moving bar or stream of dough that passes through a conduit to dough processing equipment. The processing equipment can include, among others, a dough distribution manifold which distributes the stream of dough into multiple streams of dough, a dough divider which continually divides the dough streams into pieces of dough of equal volume and deposits the dough pieces in multiple columns of dough pieces onto a moving belt of a surface conveyor for further processing along a processing path.
Extrusion-type dividers, such as described in U.S. Pat. Nos. 5,356,652, 5,270,070, 5,264,232, 4,948,611, 4,424,263 and 4,332,538, for instance, for dividing dough streams into dough pieces are well known in the prior art and typically utilize vacuum pressure to draw dough into the divider and either a single or a double screw to deliver the dough through dough conduit to a metering pump. The metering pump runs at constant speed and provides a volumetrically consistent stream of dough which is then chopped off into dough pieces of equal volume. By utilizing these extrusion-type dividers, the formation of bread-sized dough pieces (dough pieces with a scaling weight of approximately 18-32 ounces) at a rate of 200 dough pieces per minute is not uncommon.
After baker's dough has been mixed, the dough begins to develop CO.sub.2 and begins to expand or rise as it ages. As the dough is being handled by the aforementioned processing equipment, it is important that the gluten structure of the dough not be allowed to deteriorate, such as can occur by shearing, tearing, stretching or maintaining the dough at elevated pressures for prolonged periods of time. Maintaining a pliable gluten structure provides a final product which has a uniform grain structure with the gluten structure forming the walls of small pockets that trap the CO.sub.2 gas being formed within the dough, and the walls providing the tight, even grain structure desired for fine grain bread products. However, in a typical commercial bread making process for the manufacture of specialty dough products, i.e. hard rolls, pumpernickel, frozen doughs, etc, processing dough in the aforementioned manner produces an inferior product and has been considered unsuitable.
Heretofore, specialty dough products typically are manufactured by a process known as ram and shear. As shown in FIGS. 1A-1C, a typical ram and shear system 500 incorporates a hopper 502 containing a mass of dough to be processed 504 (50 pounds of water per 100 pounds of flour in the dough is common), and a blade or shear 506 that reciprocates across the bottom of the hopper between a retracted position 508 (FIG. 1C), where the bottom of the hopper is opened, and a cutting position 510 (FIG. 1A), where the bottom of the hopper is closed. A cavity 512 is provided beneath the shear 506, and a ram 514 is provided for reciprocating within the cavity. A block 516 cooperates with the cavity 512 and includes a dough-receiving cylinder 518 and a piston 520 that are arranged opposite the ram 514. The block 516, and its cylinder 518 and piston 520 are movable between a dough-receiving position 522 (FIG. 1A), where the cylinder communicates with the cavity, and a dough-depositing position 524 (FIG. 1C), where dough 504 drawn into the cylinder is expelled by the piston onto a moving belt 526 of an endless belt-type conveyor, for instance.
In operation (FIG. 1A), the shear 506 is pushed to its cutting position 510, thereby closing the bottom of the hopper 502 and trapping a portion of dough in the cavity 512. The ram 514 is then pushed into the cavity (FIG. 1B) so that the dough trapped in the cavity is pushed into the cylinder of the block 518, which is oriented in its dough-receiving position 522. The ram 514 continues to push the dough from the cavity and into the cylinder until the piston 520 is forced against its stop 528, thereby ensuring that a pre-measured portion 530 of dough 504 is pressed into the cylinder. The block 516 then moves to its dough-depositing position 524 (FIG. 1C), where an upper portion of the block seals the cavity 512. The piston 520 then slides through the cylinder 518, pushing the pre-measured portion 530 of dough out of the cylinder and onto a moving belt 526 of an endless belt-type conveyor. As the dough portion 530 is being deposited onto the belt, the shear 506 pulls back to its retracted position 508, which opens the bottom of the hopper, and the ram 514 pulls bake, thereby drawing a vacuum which draws dough 504 from the hopper and down into the cavity 512 in front of the ram (FIG. 1A). This procedure is then repeated as necessary.
Some of the prior art ram and shear systems simultaneously operate multiple S pistons, i.e. 4-8 pistons, in order to increase dough piece output. However, the prior art ram and shear systems typically are limited to a maximum operating speed of approximately 25 strokes per minute, e.g. 100 dough pieces per minute for systems utilizing 4 pistons to 200 dough pieces per minute for systems utilizing 8 pistons.
In an effort to further increase the productivity of specialty bread manufacture, attempts have been made to produce specialty breads on modern extrusion-type dough processing equipment, e.g. equipment that provides a continuous flowing dough stream. However, processing specialty dough through an extrusion-type divider to produce a continuous flowing dough stream typically results in a final product that has an undesirable fine grain structure (which is very desirable in white breads, for instance), or has numerous other undesirable qualities, such as lacking in volume, having a shortened shelf life, etc. As a result, extrusion-type dough dividers have not, heretofore, been able to penetrate the market for specialty products.
Therefore, it is desirable to provide improved dough processing methods and systems which address these and other shortcomings of the prior art.